What Is Infrared?
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Infrared is a wireless method of connecting various devices to one another using the wavelengths from the infrared part of the electromagnetic spectrum.
What Is It Used For?
Infrared technology is used when transmitting data over a small/medium range, as infrared radiation cannot travel through solid objects in the same way Bluetooth and Wi-Fi signals can.

How It Works
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Infrared technology can operate in two different modes: line-of-sight and diffuse.

Line-of-sight mode:In line-of-sight mode, there must be visually unobstructed space between the IR transmitter and the IR receiver.
Diffuse mode:In diffuse mode doesn't require the transmitter and the receiver to be in direct line-of-sight.
IR Wireless Speeds:
IrDA-SIR
115Kbps
IrDA-MIR
1.15Mbps
IrDA-FIR
4Mbps